Cyclic helix B peptide ameliorated the sepsis-induced injury in human HPMEC cells through regulating NF-κB

Sepsis is a life-threatening condition. The incidence of severe sepsis is increasing. Sepsis is often complicated with organ dysfunctions. Cyclic helix B peptide (CHBP) is a peptide derivant of erythropoietin with powerful tissue-protective efficacies. However, the role of CHBP in sepsis-induced injury remains unclear. Lyso-phosphatidylserine (LPS) was used to induce sepsis in human pulmonary microvascular endothelial cells (HPMECs). Cell growth was detected using Cell Counting Kit-8. Cell permeability was measured using fluorescein isothiocyanate (FITC)-dextran. Cecal ligation and puncture (CLP) method was applied to induce sepsis and CHBP was provided to test its efficacy. Western blot assays were used to evaluate gene expression. Administration of CHBP ameliorated LPS-induced injury in HPMECs dose-dependently. Administration of CHBP decreased the permeability of LPS-treated HPMEC cells in a same way as well. Furthermore, we identified that recombinant CHBP protein (Re-CHBP) ameliorated CLP-induced injury in vivo. Finally, we found that administration of NF-κB activator, TNF-α, abolished the function of Re-CHBP in LPS-treated HPMEC cells. CHBP ameliorated sepsis-induced injury dose dependently both in vitro and in vivo through decreasing the permeability of HPMEC cells via suppressing NF-κB signaling and inflammation. Present findings highlight the importance of CHBP/NF-κB signaling in septic injury and provide new insights into therapeutic strategies for sepsis-induced injury.